1. Field of the Invention
The present invention relates broadly to pressure-responsive valves for fluid dispensing containers, and is more particularly directed to a method for manufacturing a pressure-responsive valve having high restoration forces and to an article containing such an integral liquid-release valve.
2. Description of the Related Art
Many fluid materials, especially liquids and pastes, and especially those useful in the fields of personal hygiene, cosmetics and toiletries, employ materials that deteriorate during extended storage. Thus, for example, many perfumes, colognes, aftershaves and the like contain alcohol as an important constituent. The evaporation of the alcohol over a long period of time deteriorates the material. Almost everyone has experienced the difficulty or futility of trying to remove toothpaste from a tube that has been left open; oftentimes one encounters a blockage of dried out toothpaste which prevents further use of the tube without gouging the dried material out of the neck. Similar problems arise in the storage of lotions, creams and the like. Likewise, many industrial materials which employ volatile solvents and may encounter similar problems.
FIGS. 1 and 2 show an embodiment of the pressure responsive valve disclosed in U.S. Pat. Nos. 4,620,648 and 4,693,623, both of which are incorporated herein by reference. Referring to FIG. 1, the basic concept of this pressure sensitive valve of the prior art is disclosed. The valve 10 comprises a diaphragm 12 of elastically deformable material. For most applications, diaphragm 12 can be made of metal or plastic, of elastically deformable metal such as certain steels useful for particular applications, or of a variety of elastically deformable plastic materials. Among the plastics which appear to have important utility in the present invention are polyethylene, polypropylene, polyvinylchloride and polystyrene.
The diaphragm is provided with two or more arcuate slits, here shown as three in number identified by the reference numerals 14a, 14b and 14c. Each of the slits 14a-14c are shown to be circular, that is of a fixed radius, although other curve or curvilinear forms may be employed in defining the arcuate slits 14. Thus, for example, the slits may be portions of spirals or helixes or a part of a sine curve or an Archimedes spiral.
Extending between the two ends of each arcuate slit 14a, 14b and 14c is an imaginary line, hereinafter referred to as the xe2x80x9cbasexe2x80x9d of the slit. The bases are designated with the reference characters 15a, 15b and 15c. In the embodiment of the prior art valve shown in FIG. 1, at least one of the arcuate slits must intersect the base of another of the slits and should not curve around to intersect its own base. The slits are preferably equiangularly distributed on diaphragm 12.
The diaphragm 12 is located over or in an opening in a container such as a deformable (squeeze) bottle, or tube or the like in which is stored or disposed a supply of flowable material such as a liquid or a paste, although in certain instances gases might be so stored, to normally prevent fluid flow out of the container. The valve is normally closed, i.e. the diaphragm is undeformed with the slits closed. The valve may be operated to assume its open position by pressurizing the contents of the container against the inner surface of the diaphragm to apply a pressure differential across the diaphragm such that an outwardly directed force causes the valve to flex outwardly and open it along the slits 14a, 14b and 14c. The flexing of diaphragm 12 causes a rotation of the center with respect to the outer periphery as it moves outward in response to the force resulting from the applied pressure differential. Accordingly, upon relaxation or release of the inner pressure, the restorative force of the resilient material of the diaphragm will be sufficient to cause the deflected portion of the diaphragm to rotate in the opposite direction from the rotated direction experienced upon opening of the valve, and thereby cause and permit the deformed diaphragm portion to move back into the plane of the diaphragm and close the valve.
FIG. 2 shows the basic valve 10 of FIG. 1 in a modified form 110 incorporated into the neck 120 of a bottle 122 as a combined valve and applicator. The valve 110 and applicator 124 includes a diaphragm 112 of substantially identical configuration to the diaphragm 12 in FIG. 1, modified, however, so that the peripheral edge 16 of diaphragm 12 is integrally formed in the FIG. 2 embodiment with an upwardly extending peripheral wall portion 118 that is sealingly disposed, as by press-fit engagement, in the neck 120 of bottle 122. The press-fit engagement effectively seals and seats the diaphragm 112 such that an associated applicator pad 124 can be disposed as shown. Although not necessary, peripheral wall 118 may include an outwardly directed flange 119 to enhance the seal between the diaphragm 112 and bottle 122. The applicator pad 124 is typically formed of a material that is permeable to the fluid contained within the bottle, such as an open cell foam material or the like as is known. Such materials are themselves often elastically or resiliently deformable, permitting the resulting valved fluid dispenser to be employed as a dauber or dabber or other applicator by which the stored fluid is applied to a workpiece or surface by pressing the pod against the surface.